scholarly journals Trace Elements, PPARs, and Metabolic Syndrome

2020 ◽  
Vol 21 (7) ◽  
pp. 2612 ◽  
Author(s):  
Yujie Shi ◽  
Yixin Zou ◽  
Ziyue Shen ◽  
Yonghong Xiong ◽  
Wenxiang Zhang ◽  
...  

Metabolic syndrome (MetS) is a constellation of metabolic derangements, including central obesity, insulin resistance, hypertension, glucose intolerance, and dyslipidemia. The pathogenesis of MetS has been intensively studied, and now many factors are recognized to contribute to the development of MetS. Among these, trace elements influence the structure of proteins, enzymes, and complex carbohydrates, and thus an imbalance in trace elements is an independent risk factor for MetS. The molecular link between trace elements and metabolic homeostasis has been established, and peroxisome proliferator-activated receptors (PPARs) have appeared as key regulators bridging these two elements. This is because on one hand, PPARs are actively involved in various metabolic processes, such as abdominal adiposity and insulin sensitivity, and on the other hand, PPARs sensitively respond to changes in trace elements. For example, an iron overload attenuates hepatic mRNA expression of Ppar-α; zinc supplementation is considered to recover the DNA-binding activity of PPAR-α, which is impaired in steatotic mouse liver; selenium administration downregulates mRNA expression of Ppar-γ, thereby improving lipid metabolism and oxidative status in the liver of high-fat diet (HFD)-fed mice. More importantly, PPARs’ expression and activity are under the control of the circadian clock and show a robust 24 h rhythmicity, which might be the reasons for the side effects and the clinical limitations of trace elements targeting PPARs. Taken together, understanding the casual relationships among trace elements, PPARs’ actions, and the pathogenesis of MetS is of great importance. Further studies are required to explore the chronopharmacological effects of trace elements on the diurnal oscillation of PPARs and the consequent development of MetS.

Reproduction ◽  
2009 ◽  
Vol 137 (6) ◽  
pp. 1007-1015 ◽  
Author(s):  
Sarah J Holdsworth-Carson ◽  
Michael Permezel ◽  
Greg E Rice ◽  
Martha Lappas

Approximately 8% of births are complicated by preterm delivery. To improve neonatal outcomes, a greater understanding of the mechanisms surrounding preterm parturition is required. Peroxisome proliferator-activated receptors (PPARs) have been implicated in the regulation of labor at term where they exhibit anti-inflammatory properties. Thus, we hypothesize that dysregulation of PPAR expression and activity may be associated with preterm labor and infection-associated preterm labor. The aim of this study was to compare the expression and activity of PPARs and the expression of retinoid X-receptor α (RXRA) in gestational tissues from term and preterm deliveries, and from infection-associated preterm deliveries. Quantitative RT-PCR, western blotting and activity ELISA were used to study expression and DNA binding profiles. Compared with term, preterm parturition was associated with an increased expression of PPAR δ (PPARD; mRNA and protein), PPAR γ (PPARG; protein) and RXRA (protein) in the placenta and PPARD (mRNA and protein) and RXRA (mRNA) in the choriodecidua. There was, however, no change in preterm PPAR DNA binding activity compared with term. Preterm chorioamnionitis (CAM) demonstrated protein degradation in the choriodecidua and was associated with a decline in the mRNA expression of PPAR α (PPARA) and RXRA compared with uninfected preterm cases. PPAR DNA binding activity increased in the placenta (PPARD and PPARG) and decreased in the amnion (PPARA and PPARG) in association with preterm CAM. In conclusion, idiopathic preterm deliveries were associated with an increase in PPAR:RXR expression and preterm CAM was associated with a decrease in PPAR:RXR expression and tissue-specific alterations in transcriptional activity. The reasons for such dysregulation remain to be determined; however, the data are consistent with the hypothesis that PPARs may play a role in preterm labor and infection-complicated preterm deliveries.


2002 ◽  
Vol 282 (1) ◽  
pp. C125-C133 ◽  
Author(s):  
Marie-Agnès Simonin ◽  
Karim Bordji ◽  
Sandrine Boyault ◽  
Arnaud Bianchi ◽  
Elvire Gouze ◽  
...  

This work demonstrated the constitutive expression of peroxisome proliferator-activated receptor (PPAR)-γ and PPAR-α in rat synovial fibroblasts at both mRNA and protein levels. A decrease in PPAR-γ expression induced by 10 μg/ml lipopolysaccharide (LPS) was observed, whereas PPAR-α mRNA expression was not modified. 15-Deoxy-Δ12,14-prostaglandin J2(15d-PGJ2) dose-dependently decreased LPS-induced cyclooxygenase (COX)-2 (−80%) and inducible nitric oxide synthase (iNOS) mRNA expression (−80%), whereas troglitazone (10 μM) only inhibited iNOS mRNA expression (−50%). 15d-PGJ2 decreased LPS-induced interleukin (IL)-1β (−25%) and tumor necrosis factor (TNF)-α (−40%) expression. Interestingly, troglitazone strongly decreased TNF-α expression (−50%) but had no significant effect on IL-1β expression. 15d-PGJ2 was able to inhibit DNA-binding activity of both nuclear factor (NF)-κB and AP-1. Troglitazone had no effect on NF-κB activation and was shown to increase LPS-induced AP-1 activation. 15d-PGJ2 and troglitazone modulated the expression of LPS-induced iNOS, COX-2, and proinflammatory cytokines differently. Indeed, troglitazone seems to specifically target TNF-α and iNOS pathways. These results offer new insights in regard to the anti-inflammatory potential of the PPAR-γ ligands and underline different mechanisms of action of 15d-PGJ2 and troglitazone in synovial fibroblasts.


2019 ◽  
Vol 99 (4) ◽  
pp. 764-771 ◽  
Author(s):  
Baojun Li ◽  
Liying Qiao ◽  
Xiaoru Yan ◽  
Tao Shi ◽  
Duanyang Ren ◽  
...  

Fat deposition in animals involves adipogenic differentiation guided by transcriptional factors and other key factors. To understand the molecular mechanism underlying ovine adipogenic differentiation, the dynamic mRNA expression of key genes related to fat deposition, including peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid-binding protein 4 (FABP4), FABP5, and cellular retinoic acid-binding protein 2 (CRABP2), were analyzed during in vitro differentiation of ovine preadipocytes. The stromal vascular cells from underneath the tail fat tissue of 1-wk-old sheep were isolated and cultured, and the preadipocytes were induced using a cocktail of 3-isobutyl-1-methylxanthine, insulin, dexamethasone, and troglitazone. The cultivated cells were collected at different time points after induced differentiation. The expression levels of PPAR-γ, FABP4, FABP5, and CRABP2 were studied by quantitative real-time polymerase chain reaction. The expressions of these genes in sheep were compared with those in human and mouse retrieved from the Gene Expression Omnibus DataSets. We observed that the expression of PPAR-γ, FABP4, and FABP5 was increased upon differentiation of ovine preadipocytes, as in humans and mice. The expression of CRABP2 was sharply increased from days 0 to 2 after induced differentiation and was subsequently decreased. This expression pattern of CRABP2 was different from that observed in humans and mice. Our results provide new insights into the function of these genes in fat deposition.


PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0188596 ◽  
Author(s):  
Marijana Sekulic-Jablanovic ◽  
Vesna Petkovic ◽  
Matthew B. Wright ◽  
Krystsina Kucharava ◽  
Nathan Huerzeler ◽  
...  

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1386 ◽  
Author(s):  
Danyelle M. Liddle ◽  
Meaghan E. Kavanagh ◽  
Amanda J. Wright ◽  
Lindsay E. Robinson

Adipose tissue (AT) expansion induces local hypoxia, a key contributor to the chronic low-grade inflammation that drives obesity-associated disease. Apple flavonols phloretin (PT) and phlorizin (PZ) are suggested anti-inflammatory molecules but their effectiveness in obese AT is inadequately understood. Using in vitro models designed to reproduce the obese AT microenvironment, 3T3-L1 adipocytes were cultured for 24 h with PT or PZ (100 μM) concurrent with the inflammatory stimulus lipopolysaccharide (LPS; 10 ng/mL) and/or the hypoxia mimetic cobalt chloride (CoCl2; 100 μM). Within each condition, PT was more potent than PZ and its effects were partially mediated by peroxisome proliferator-activated receptor (PPAR)-γ (p < 0.05), as tested using the PPAR-γ antagonist bisphenol A diglycidyl ether (BADGE). In LPS-, CoCl2-, or LPS + CoCl2-stimulated adipocytes, PT reduced mRNA expression and/or secreted protein levels of inflammatory and macrophage chemotactic adipokines, and increased that of anti-inflammatory and angiogenic adipokines, which was consistent with reduced mRNA expression of M1 polarization markers and increased M2 markers in RAW 264.7 macrophages cultured in media collected from LPS + CoCl2-simulated adipocytes (p < 0.05). Further, within LPS + CoCl2-stimulated adipocytes, PT reduced reactive oxygen species accumulation, nuclear factor-κB activation, and apoptotic protein expression (p < 0.05). Overall, apple flavonols attenuate critical aspects of the obese AT phenotype.


Blood ◽  
2001 ◽  
Vol 97 (3) ◽  
pp. 692-699 ◽  
Author(s):  
Toshiya Nishibe ◽  
Graham Parry ◽  
Atsushi Ishida ◽  
Salim Aziz ◽  
Jacqueline Murray ◽  
...  

Abstract Tissue factor (TF), a transmembrane glycoprotein, initiates the extrinsic coagulation cascade. TF is known to play a major role in mediating thrombosis and thrombotic episodes associated with the progression of atherosclerosis. Macrophages at inflammatory sites, such as atherosclerotic lesions, release numerous cytokines that are capable of modulating TF expression. This study examined the role of oncostatin M (OSM), a macrophage/ T-lymphocyte–restricted cytokine, in the expression of TF in vascular smooth muscle cells (SMCs). It is reported here that OSM stimulated a biphasic and sustained pattern of TF messenger RNA (mRNA). The effect of OSM on TF mRNA expression was regulated at the transcriptional level as determined by nuclear run-offs and transient transfection of a TF promoter-reporter gene construct. OSM-induced TF expression was regulated primarily by the transcription factor NF-κB. Activation of NF-κB by OSM did not require IκB-α degradation. Inhibition of MEK activity by U0126 prevented OSM-induced TF expression by suppressing NF-κB DNA binding activity as determined by gel-shift analysis. Further, inhibition of Erk-1/2 protein by antisense treatment resulted in suppression of TF mRNA expression, indicating a role for Erk-1/2 in modulating NF-κB DNA binding activity. These studies suggest that the induced expression of TF by OSM is primarily through the activation of NF-κB and that activation of NF-κB is regulated in part by the MEK/Erk-1/2 signal transduction pathway. This study indicates that OSM may play a key role in promoting TF expression in SMCs within atherosclerotic lesions.


2017 ◽  
Vol 29 (6) ◽  
pp. 1074
Author(s):  
Ratana Lim ◽  
Gillian Barker ◽  
Martha Lappas

Spontaneous preterm birth remains the major cause of neonatal death and morbidity. Studies in non-gestational tissues report that optineurin (OPTN) is critical in the termination of NFKB1 activity and control of inflammation, central features of spontaneous preterm birth. The aims of the present study were to determine: (1) OPTN expression in fetal membranes and the myometrium during labour; (2) the effects of IL1B on OPTN expression in primary myometrial cells; and (3) the effects of OPTN short interference (si) RNA on IL1B-stimulated proinflammatory and prolabour mediators. OPTN mRNA and protein expression was significantly decreased with spontaneous term labour in fetal membranes and the myometrium. Although there was no effect of spontaneous preterm labour on OPTN expression in fetal membranes, there was decreased OPTN expression in membranes with chorioamnionitis and myometrial cells treated with 1ng mL–1 IL1B for 1 or 6 h. In cells transfected with OPTN siRNA, significant increases were seen in IL1B-stimulated IL6, tumour necrosis factor, CXCL8 and monocyte chemoattractant protein-1 mRNA expression and release, cyclo-oxygenase-2 and prostanoid PTGFR receptor mRNA expression and the release of prostaglandin F2α. There was no change in IL1B-stimulated NFKBIA expression; however, there was increased NFKB1 p65 DNA-binding activity. The results of the present study suggest that OPTN is a negative regulator of inflammation-induced prolabour mediators.


2017 ◽  
Vol 212 ◽  
pp. 22-32 ◽  
Author(s):  
Motoki Kai ◽  
Makoto Miyoshi ◽  
Mayu Fujiwara ◽  
Yuya Nishiyama ◽  
Taketo Inoue ◽  
...  

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